Burring tool



June 5, '1945- c. A. Tl-:A ET AL 2,377,462

I BURRING TOOL Filed Feb. 22, 1943 INVENTORS Patented June 5, 1945UNITED STATES PATENT' QFFICE 2,377,462 f f poniamo 'root Clark A. Tea,Detroit, and KarlH. Luther, Dearborn Township, Wayne County; Mieli.,assign-i ors to The Murray Corporation of America, Detroit, Mich., acorporation of Delaware Application February 22, 1943, serial No.476,682

Claims.

This invention relates to burring too1s, ahd particularly to a burringto'ol having a piloted cutter which is rotated a predetermined amountunder a predetermined pressure toy perform the burring operation.

When holes' are drilled in sheets of aluminum, the metal adjacent to thehole burrs outwardly of both faces ofthe sheets and must be removed,before a riveting operation is performed thereon. Drills and likecutting ltools were handern'anipu`v lated in the apertures for' removingthe burrs, but, since the amount of pressure and rotation of the toolwas left to the judgment of the oper'- ator, the surface oi the metalWaseither darn" aged or the' aperture was chamfered because too muchmetal was retrieved.

The present tool overcomes this diiiiculty by controlling the amount ofpressure'v which may be applied and the amount of rotation erripl'oye'dvwhen performing the burring operation'. mille ing type of cutter isutilized which readily cuts away the metal of the burr when rotatedprei'determined amount under' an applied pressure produced by thecutter-supporting tool'. The cut-` ter is provided With a pilot on theend which pro`- jects int-"o the aperture andv locatesjthe cutterrelative to the burr, which is quickly` reiiioved without damaging thernetall adjacentto the aper-` ture. Only a slight clearance angle isprovided on the cutting edges, so that the burr maybe' entirely' removedWitltio'utI damaging' the Surface of the sheet'.

The tool embodies a spindle', on the endvof which the cutting tool isthreaded or otherwise secured and about which a `v'vire is helicallyattached and received by a slot in afy flange on atube which extendsvover the spindle. The tube contains af'spring which rests' uponl asleeve' disposed over the spindle and alouts` against the end of ahandle which is secured to' the end 0f the tube. utlet openings? areprovided through the tube, and the' handle for permitting the escape"ofV air which' would othc ervvisek be trapped within the hollow' spaceof' the handle and tube. A Y

When a burr' is to' be' removed from an aper-4 ture in d sheet, thecutting tool issiipportedhoh the eineV of' the aperture by' the pilotextending forwardly' of the Cutting face. Thelf'i'andl'e is' pushedtoward the. sheet to provide a`- predeter'e mined pressure' to the'cutting tool which is rotated through the' action of the flange of thesleeve operating over the helical Wire disposed about the spindle. Thehelical disposition of wire is such that substantially one and one-halfturns `quired to remove the burr.

Accordingly, the main objects of this inven-v tion are: to provide atool for removing the burr's about rapertures which produces api"edet'eriniiedv number of revolutions under' predetermined springpressure for each operationito prvidea buriihg too; hdvirigpa rotatablespindle' and a' piloted Cutting. tool oli the velid Which is rotated bythe movement of en operating handle over the spindle while applyingapredetermined pressure thereto; to' providey a biin'g" tool for remvingthe burrs of apertures, comprising, a spindle havinga helical Wireweldedk or' otherwise secured thereto, which engages a slot in a tubeWlich'is' supported by a handle in Iu/"hicha sprint-g"y isf dise posedvfor applying a predetermined pressure to -tlie'tool as the' tool isrotated by ampi/'ement of the handle and; .tube over` the spind1e; aiid,in general, to provide a tool for rer'noving'burrs which is simple inconstruction, positive in oper ation, and economical of manufacture.

ther objects' and features ,of novelty of this invention Will beSpecifically pointed out or Will become apparentwhen referring, for abetter un; destaidig 0f the invention, to the following description,taken in conjunction with the aco'rripanying drawing, wherein: Y

Figure 1 is a view in elevation of a burring tool embodying features ofthis invention;

Fig. 2 isdn emerged seetioiiai view of the strue-l tiire iuus'trat'ed inFig; 1, taken on the line 2'i-2 thereof;

Fig. 3 is an enlarged sectional view of the struc-'- ture illustrated inFig. 2', taken' on the line A3`3 thereof:

Fig 4 is an enlarged, broken sectional viev'v o'f tlie structureVillustrated Fig'. 2`, within the circle indicated by the numeral 4; v

5* is an enlarged broken sectional View of that .portion of the toolillustrated injFig. 2, Within thecircle indicated by' the numeral 52 and6 is' an endieWof the' s'tructllreillustlted in Fig. 5, S viewed fromline- 6.-"6 theref.

Theburring toolfcoriprises a'.` spindle Ill' having a helical Wire" H@Welded vor otherwise secured tl'ie'ret'ol upper e'd of the Wire isforined in a loop I2 received Within a ange I3 of a sleeve I4. The wireextends through a slot I5 within the i flange I 3 which produces therotation of the spindle as the ilange moves downwardly thereover. Asleeve I6 is rotatively disposed over the upper end of the spindleadjacent to the loop I2. A spring I'I is disposed over the upper end ofthe spindle IIJ in abutting relation to the sleeve I6, while the upperend extends over` a rubber bumper I8 within the hollow interior 24 of ahandle I9 which is secured to the end of the sleeve I4.

A plurality of apertures 2| extend through the handle and the sleeveabove a ferrule 23 attached to the lower portion of the handle. Thepassage- Ways formed by the apertures permit the escape of air fromwithin the sleeve and the hollow interior 24 of the handle, so that theonly pressure that can be applied to the spindle will be that of thespring I1. In view of the locked or trapped air within the handle, therubber bumper I8 is relied upon for cushioning the engagement of thespindle I therewith. The lower end of the spin- 'dle I 2 is threaded at26 for receiving the threaded stem 2'I of the cutting tool 28. Aplurality of cutting edges 29 are provided on the end face of the toolwhich are disposed at an angle to the tool axis and provided with reliefand chip-receiving recesses in the conventional manner. A pilot 3|extends forwardly of the end of the tool on the tool axis and may bepress-iitted within an aperture in the end of the tool or otherwisesecured thereto.

In operation, when a burr is to be removed from the edge of an aperture,the pilot 3| is disposed within the aperture and pressure is applied atthe handle to move the sleeve I4 over the spindle I0. The spring I1provides a predetermined pressure to the cutting tool 28 while rotationis applied thereto through the movement of the flange I3 of the sleeveover the helically disposed wire II. The pressure and rotation providedto the spindle are sulcient to produce a burring operation with a singlemovement of the handle.

This assures the removal of the burr without removing metal from thewall of the aperture. The tool eliminates the personalequation which waspresent heretofore when an ordinary drill or similar tool was manuallymanipulated for removing the burrs.

What is claimed is:

l. In a burring device, a rotatable spindle, a wire helically disposedon such spindle in iixed engagement therewith throughout the length ofthe wire, a sleeve longitudinally movable over said spindle havingdriving engagement with the wire to rotate said spindle, a spring withinsaid sleeve for regulating the pressure applied to the spindle, and acutter on the end of the spindle having a plurality of relieved cuttingedges which are rotated over the burr a predetermined number of timesundena predetermined pressure as the sleeve is moved over the spindle. l

2. In a burring device, a rotatable spindle, a cutting tool on the endof said spindle, a sleeve longitudinally movable over said spindle, ahollow handle on said sleeve, a spring disposed over said spindle withinsaid handle for applying a predetermined pressure thereto, a wirehelically disposed labout the body of the spindle in contact therewithand secured thereto in iixed position, a flange on the end of saidsleeve having a slot to receive said wire for producing the rotation ofthe spindle when the sleeve is longitudinally moved thereover, and aplurality of apertures ex tending through said sleeve for providingcommunicating passageways between the interior and the exterior of saidsleeve to prevent the pressure of air within the handle from applying agreater force than that applied through the spring which is proportionedto produce a burring operation with a single movement of the sleeve.

3. In a burring tool, a spindle, a wire helically disposed on saidspindle having a loop at its upper end and engaging the spindlethroughout its length, a sleeve having an inturned slotted flangedisposed over said spindle, wire, and said loop. a second sleeve on theupper end of said spindle abutting said loop, a spring having one enddisposed over said spindle and abutting the end of said second sleeve, ahandle supported on said rst sleeve having a hollow interior forreceiving the other end of said spring, a cutter secured to the end ofsaid spindle having a plurality of cutting edges on its end face, and apilot extending from the end of said cutter on the axis thereof, thetension of the spring being proportioned to the helical lead of the wireand the number of cutting edges of the tool to produce the necessaryannular movement to the cutting tool with a predetermined pressure toperform a burring operation with a single forward movement of thehandle.

4. In a device for removing burrs from an aperture in an element, aspindle, a helically disposed wire surrounding and snugly engaging saidspindle and secured in iixed relation thereto, a sleeve extending oversaid spindle and wire having an inwardly disposed flange containing aslot in which the wire projects, a tubular element disposed over theupper end of said spindle in engagement with one end of said wire, aspring abutting said element, a hollow handle disposed on the outer endof said sleeve into which the outer end of the spring projects, and aburring tool on the end of the spindle having a plurality of cuttingedges, the tension of the spring, the slope of the helix on which thespring is disposed and the number of cutting edges being so proportionedrelative to each other as to have the edges completely remove a burrwithout damaging the metal about the aperture upon a single completemovement of the handle.

. 5. In a device for removing burrs from the edge of an aperture of anelement, a spindle, a helically disposed wire surrounding said spindlehaving its lower end welded thereto and having a loop on its upper endencompassing said spindle, a sleeve extending over said spindle and wirehaving an inwardly disposed flange containing a slot in which said wireprojects, a tubular element on said spindle having one end abutting saidloop, a hollow handle disposed on the outer end of the spindle, a springwithin said sleeve having one end engaging said tubular element and lcheother end abutting the handle, and a burring tool on the outer end ofthe spindle, the interior of said handle being connected by a passagewayto the exterior thereof t0 prevent pressure from building up thereinwhich would increase the applied pressure over that produced by thespring, the tension of which is proportioned to the degree of rotationproduced to the spindle and the cutting characteristics of the tool toproduce a burring operati n upon the complete movement of the sleeve 0&1the spindle.

CLARK A. TEA. KARL H. LUTHER..

